This invention relates to protective relaying apparatus for an electric power system, and more particularly to protective relaying apparatus for detecting a fault or locating the fault.
With the recent increase in power demand, the importance of protective relaying apparatus in electric power systems has increased. Thus, the protective relaying apparatus are required to have better operating characteristics. For this reason, it is a recent trend to substitute relaying apparatus utilizing electronic elements such as transistors or the like for the electromagnetic mechanical type in view of the operating speed, the burden of the relay circuit, and the sensitivity of the relaying apparatus. Prior art relaying apparatus can be classified into the following two types but each of them has the following defects.